Multihoming enterprise

[hhyten]

Hello.

A customer has two ISPs, each in a different city. The ISP in the main office goes down occasionally and they want the other ISP to serve as a backup for the whole firm when this happens.

Their environment: Connection to ISP in each city is via a Cisco 2610 that sits in front of a PIX 515 running OS 5.3.1. EIGRP routing inside, using 10.0.0.0 private addresses. Each PIX is doing single-address NAT (PAT, whatever). A 2610 in each city has the default gateway that routes out the PIX.

I've read http://www.cisco.com/warp/public/cc/pd/iosw/ioft/ionetn/tech/emios_wp.htm though had trouble deciphering it. I am also afraid that the PIXes might interfere with this particular config since they're the ones doing NAT, not the routers.

From what I gather, I need to set up BGP between the two ISPs. I've not had to deal with BGP and ISPs before and am not looking forward to it. In addition to technical instructions and advice, any words of wisdom dealing with them would be appreciated too.

Thanks in advance,

-Howard

hhyten@yahoo.com

[awilliamson]

I was in the same boat at one time... :)

I dwelled off the technical expertise of the ISP in order to establish BGP connectivity, usually they have only a certain way for you to implement it with them anyway. I'd just ask for their assistance in connecting it up.

Another thing you might want to look into is using HSRP on the ethernet interfaces of the routers as well...that way when the primary link is down all outbound traffic would flow threw the secondary router...in effect, one less hop out.